The proposed research is focused on analyzing the regulatory components that are required for the transcription expression of a specific set of genes during conditions of low oxygen-stress in Zea mays. Low-oxygen stress overrides the normal developmental program of gene expression and induces the synthesis of a class of gene products designated the "anaerobic polypeptides'. There is a lot of information about the anaerobic response in maize, and one of the anaerobic polypeptides--alcohol dehydrogenase-1--has been extensively characterized genetically and biochemically. This proposal is aimed at exploiting the genetic analysis of cis-acting regulatory elements of the maize alcohol dehydrogenase-1 gene to examine the biochemical factors that are required for gene expression during anaerobiosis. The methods proposed include both in vitro DNA-protein binding assays and in vivo footprinting techniques to identify, characterize, and isolate the regulatory proteins that are required for anaerobic induction of gene expression. These studies are an important step in unravelling the regulatory mechanisms that are responsible for the expression of genes in response to external factors.